Pipes such as fuel pipes, brake pipes, and cooling system pipes are typically disposed in an engine room and the like of an automobile. These pipes are subject to vibrations of the automobile. In order to prevent those vibrations from reaching the pipes, a method has been employed in which the pipes are held by clamps.
One related pipe clamp is a resin clamp structured such that a clamp body is formed integrally with a pipe holding portion. The clamp sandwiches the pipe, such as a fuel pipe, at that pipe holding portion.
Also, Japanese Utility Model Publication No. 6-6253, for example, proposes a clamp that includes a pair of clamp members that sandwich a plurality of pipes. This clamp is structured such that each clamp member includes an elastic body having a plurality of concave portions formed therein and a reinforcing plate that is fixed to an outer side surface of this elastic body. The pair of clamp members are then aligned with the pipes arranged in the concave portions of the elastic bodies such that the plurality of pipes are fixed in place at the concave portions. The clamp according to Japanese Utility Model Publication No. 6-6253 is structured to fix and hold a plurality of pipes at concave portions in an elastic body, thus making it possible to damp vibrations acting on the held pipes.
A clamp of a structure that holds pipes at concave portions in an elastic body, such as that described above, works fine as long as the plurality of pipes all have the same outer diameter. If the plurality of pipes have different outer diameters, however, the pipes may become deformed as a result of the conditions such as the compressibility of the elastic body and the tightening allowance [(pipe diameter)-(concave portion diameter)]. Furthermore, the vibration absorption effect may not be able to be achieved.
For example, when holding a plurality of pipes having different outer diameters using a clamp of a structure which holds the pipes at concave portions of an elastic body, for example, the tightening allowance for each pipe is the same. Therefore, when that tightening allowance is a dimension appropriate for a large diameter pipe, then less force is applied to a small diameter pipe such that the hold of the clamp becomes loose. As a result, the vibration absorption effect may be reduced. If, on the other hand, the tightening allowance is appropriate for the small diameter pipe, then the force applied to a large diameter pipe ends up being excessive, possibly resulting in deformation of the large diameter pipe. There is also a possibility of the small diameter pipe becoming deformed depending on amount of compression of the elastic body.
Moreover, if the tightening allowance is the same for each pipe, the decrease in binding force between pipes of different diameters may become uneven if the pipes settle on the elastic body as it deteriorates over time. As a result, the hold of the clamp on the large diameter or small diameter pipe would become loose, such that the vibration absorption effect would no longer be able to be achieved.